THIS PROJECTILE WAS FOUND IN A CREEK BED ABOUT 15 MILES WEST OF SAN ANTONIO TX IN A DRY CREEK BED.
They are solid iron with a small cap of lead on the tip. A deep slot is present at the base.
Looking at the back portion of the projectile it appears that there was an extension of the same material attached to the base of the projectile that broke off .
It can be seen where it broke off the base on one picture.
If anyone can add any information It would be appreciated.
I have found a picture of an Army field piece that fired a 37 mm shell.
length is about 47 mm long.